Malcolm Turnbull didn’t actually trade his first-born this week but it felt like it might come to that.

In a whatever-it-takes frame of mind, the government conceded a great deal to get its legislation to resurrect the Australian Building and Construction Commission (ABCC) through on Wednesday.

So much so that Labor finds itself caught between its attack lines. Does it concentrate on arguing this is draconian legislation hitting the workers, or on claiming it has been emasculated by government backdowns?

Labor spokesman Brendan O'Connor did both. “It would have been a lot easier for Malcolm Turnbull just to change the name of the Fair Work Building Commission because of the backflips the government entertained,” he said.

But “we don’t support the ABCC, we’ve never supported the ABCC, so of course we won’t be looking to continue its conduct and its operation in government”.

This final parliamentary week is replete with contradictions and competing imperatives. It’s not a time for the politically pure.

Turnbull likes to portray himself as a pragmatist who wants this parliament to work. To achieve that he’s had to let a vigorous tail, in the form of assorted crossbench senators, wag the dog.

There have been few limits. The idea of telling the ABC and SBS boards they must have regular public forums, as part of the bid to get David Leyonhjelm’s vote on the ABCC, was little short of bizarre.

That’s not to deride the idea of the forums. Indeed Turnbull may wish he had thought of them when communications minister.

Then for Nick Xenophon there was the elevation of the Murray-Darling water issue to a permanent item on the Council of Australian Governments agenda, where it can be regularly monitored.

Xenophon got nothing of substance on water but decided to be happy enough with having its oversight raised to the level of first ministers (take that, Barnaby Joyce), with some extra scrutiny at Senate estimates.

One can take the view that amending bills often produces a better result, and removing some of the harsh edges of the ABCC legislation falls into that category.

On the other hand, the amount of power in the hands of this or that crossbencher at any particular moment, all of them claiming their own mandates and some with very specific demands outside the legislation being dealt with, is a worry.

Not that it’s new. Tasmanian independent Brian Harradine extracted huge largesse from the Howard government for his home state, and other things besides.

And it could be argued that in the last parliament there was not enough trading to make it functional.

Leaving aside the water and ABC trade-offs, the following were among the concessions made to get the ABCC bill through:

agreement to a security of payments working group to help protect subcontractors;

a requirement for preferred tenderers for government building work to provide information about the use of domestically sourced materials and the impact on jobs and skills growth;

changes to government procurement policy across the board – Australian standards will have to be met for procured goods and services, and for procurements of more than A$4 million the economic benefits to the Australian economy must be considered. This has a distinct whiff of protectionism;

a two-year grace period for companies seeking government contracts to get their enterprise agreements to comply with the new building industry code. Originally the new code would have applied retrospectively to enterprise agreements struck since April 2014, disqualifying some companies from government work;

a requirement for employers in the industry to show that no Australian worker is available before they can take on a foreign worker. This was the one successful Labor amendment, passed in the face of government opposition;

preservation of a number of the existing civil liberty safeguards available to a person subject to examination, which the original legislation would have knocked out;

a review of the act within the next year;

making decisions under the act subject to merit review; and

accepting the onus of proof should not be on employees to prove they held a reasonable concern about health or safety when ceasing work.

Labor denounced Turnbull as a “horse-trader by nature”, which he is. He’s about outcomes. In business he was about deals. When he was seeking the leadership, he “traded” earlier positions on climate policy and the same-sex marriage plebiscite as part of his pitch for votes.

When Leigh Sales on Wednesday night pointed to the deals he’d done on crossbenchers’ “pet projects” and asked “is your legislative agenda, looking forwards, going to be held hostage by all of the niche interests that all of the crossbench has?”, Turnbull replied: “Well Leigh that’s the nature of politics. We don’t control the Senate and so to secure the passage of our legislation through the Senate we have to negotiate with the crossbench.”

In this case, it was vital for Turnbull to end the year with substantive legislative achievements, which he has obtained. The two double-dissolution bills are through, with tougher union governance rules passing last week.

But having played ball, albeit at a price, on the ABCC, the Senate immediately delivered Turnbull a slap when it rejected the 15% rate for the backpackers tax, and instead voted for 10.5%.

So it was back to the trading room, with Treasurer Scott Morrison – who is so far not budging from 15% – trying to turn around the numbers.

Leyonhjelm has now accepted 15% – in return the government has agreed to drop publication of the names on the planned register of farmers and other employers of backpackers. Morrison was also working on Derryn Hinch and One Nation’s Rod Culleton – he needs one of them.

Failure to get the backpacker tax legislation passed this week would take some of the gloss off the win on the ABCC. Most obviously, it would infuriate the farmers.